MIL will go ape if I stop her Sunday visits
So what if she does? What are you frightened of? Don't you think DH will support you?
There's no way I would let a woman who puts me down, tells my own DD to ignore me, and tells DD that she is her mother (wtf?!) ruin my Sunday every week.
^^this! There's no reason whatsoever, not one, why you have to put up with this shit. Nobody can make you. It's your home & your child & you don't EVER have to entertain MIL in the absence of DH if you don't want to.
"MIL, you're not going to be able to stay overnight on Saturdays any more. It doesn't work for us".
"MIL, I need you to stop interfering when I tell DD off".
"MIL, I'm not prepared to have you tell DD that you are her mum. Don't be so daft".
"MIL, we're going to cut down these w'end visits to once a month. I want to do other things on a Sunday".
Let her go bloody ape if she wants.
"MIL, I'm sorry you're not happy about this but it's my weekend too & it's my home & that's what's going to be happening. Now fuck off, you loon ."